1. Field of the Invention
The present invention relates to an airfoil for use in a gas turbine engine, either as a blade or a vane, in which the airfoil includes a plurality of porous metal filled cavities with a thermal barrier coating applied over the porous metal, the porous metal allowing cooling air to flow through it onto the TBC producing a cooling air film to cool the airfoil.
2. Description of the Related Art Including Information Disclosed under 37 CFR 1.97 and 1.98
Prior art airfoils use a variety of ways to cool the airfoil using cooling air passing through and over the surface of the airfoil. U.S. Pat. No. 4,629,397 issued to Schweitzer on Dec. 16, 1986 shows an airfoil (FIG. 4) having a plurality of unobstructed cooling ducts 3 and lands 5 enclosed by an inner layer of metal felt 4 and an outer layer of heat insulating ceramic material 6 which partially penetrates into the metal felt 4 to form a bonding zone between the felt 4 and the ceramic material 6. Thus, any heat passing through the ceramic layer 6 is introduced into the large surface area of the metal felt 4 enabling the latter to efficiently introduce the heat into a cooling medium flowing in the ducts 3, thereby preventing thermal loads from adversely affecting the metal core to any appreciable extent.